Crop drier



R. ARNDT 2,699,769 CROP DRIER 2 sheets-sheet 1 Invenor:

his Horney Raymond Arndt Jan. 18, 1955 Filed July 5, 195o Jan. 18, 1955 R. ARNDT 2,699,769

CROP DRIER Filed LJuly 5, 195o 2 sheets-sheet :2

FIG. 3

Inventor:

Rdymond rndt V/ By w l his Attorney United States Patent C) CROP DRIER Raymond Arndt, Columbus; Nebr., assgnor toi Hbco` Manufacturing Co., Columbus, Nebr.',, a' corporationof Nebraska This invention relates, generally to` spacerheaterstand` more particularly to driers for crops;

The primary object `of1 the. invention; is `to.` provide:` an improved crop` drier for` generating, hot" air:` and forcing uhd air into a space whereinta eropnorY the` like'isato.. be

rie Y Another object of the invention is` to provide` an improved crop drierhaving` a multistage heat exchanger.` deriving its `heat. from `a` jet' burner, wherebyg` a relatively large volume of air is eiciently heated.l to a desired temperature.

Ari-additional object of theinventionistoiprovidefan` improved' crop drier in which both the combustion` air. and. air to be heated are impelled by afsinglefbloweri.`

A further object of the invention `islto `provide `an improved crop drier in which the temperatureofjthe heated' outllet air is readily regulated' and automatically.- control ed.

Other. objects and advantages of the invention will appear hereinafter in the` detailed description, be p articularly pointed out in the appended claims andi illustratedin the accompanyingtdrawings in which:-

Figure 1j is a side:elevational View of a preferredem-` bodiment 1 ofthe t improved drier of the lpresent'` invention; Figure, 2 is aside elevational view-` of the drierof Figure 1 on an enlarged scale, withportionsfbroken away and shown in sectionto morerclearly illustrate. certain ofthedetails ofvconstruction;

Figure 3 isa front endselevationaliview ofthe drier= on the scale` of Figure 2, with portibnsremoved to'more4 clearly illustrate-certain ofthe detailspof construction;

Figure 4 is. a vertical.sectionalview, taken along-fthe lines 4-4ofFigure 2; andi d,

Figure Stis averticalfsectional` view, -takenalong, the. lines 5`5 of Eigure 2. i d

Referring nowrin detailtoithe drawingstinwhich ,likereference characters designate `like .partswthe` improved drier of the present invention is particularly, designed fordryingcrops and for this :purpose-may, either be `the-.illust trated mobile unitoradapted` to` be lpermanently mounted on a suitable base, dependinglupon. ,itssapplication ForL the. illustrated mobile \unit, there. 1s .providedA asuitablefor connecting` 1t tota tractorindicateddiagrammatically at4, the tongue preferablyiwbeng` provided witlLavjacleS` position when `disengagedfor supporting the drier in level from its tractor. When on location, the drier normally will have` tsframe grounded;throughythetjaekatowprevent inadvertent explosion of its fuel. However, due to the highly combustible nature-oftthe crops which it is designed to dry,` the jack is preferably supplementedby a ground rod` 6 which, by being driven into their ground, ensuresuthat aground connection lisobt-ained, regardless of the nature of the surface on which-the` jack rests:

Mounted upon the frame 1 is the-body 7 ofrthe-.dri'er which is in the form of a cylindrical: casing.jacketfy or shell 8 of uniform cross-section-.andopen at bothends. Within this `casing isH supporteda heat exchanger designated generally as 9, which is comprisedtof a lower,1.primary tube, cylinder or heat exchange unit 10.-and:two upper, secondary tubes, cylinders or units 11, all extending axially of the casing 8 and occupying the major portion of its length, measured from the outlet end 12 of the casing. The tubes of the heat exchanger are arranged in alignment and in substantially V-shape, with the upper tubes 11 supported on the lower tube 10, the latter, in turn, being mounted within the casing on suitvfice able feet -or brackets 13. The upper of the' tubes are open I at" both- Vends 1 and i hollow-walled' throughout their lengths,- the annular spaces 14 so provided in their walls 15 being-connectedby conduits `16 to theinterior 17 of the lower tubeA 10,` adjacent the outlet end 12 ofthe casing: Adjacent their opposite or` forward. ends,- the annular vspaces 142 areI connected through a' pipe. 18, ex` tending-*axiallyfof the casing,` to an exhaust stack 19, normal to and projecting. through the casing, the stack having 'its outlet201capped and enclosed `by screening .21` towprevent egressof any burningparticles.-

Theflowertubei10preferably is conned by` al solid lateralfwall `ZZtandits `interior 17 is divided'. or compartmeiited axially toward itsinner end 23 by ani` annular partition; spacing plate 'ordisk 24 into a combustionchamber25v andan air chamber 26, which occupy, respectively, the outerand inner portions of the tube. The` aircham-` ber houses or contains a jet burner 27, comprised of`- a housing 27aconcentric with the tube and having aclosed inner endf28-`supported on a bracket 29 and an open outer end 30 projecting through and supported by the spacing plate 24. As shown, the burner is disposed inwardly of boththe endf23 and lateral wall 22 of the tube to provideV afsurrounding air spacewithin the air chamber 26, and its housing "27a has a` plurality of sets of laterally arranged openings or `ports 31 through which air is drawn .within or insidel the burner, and there directed by louvres or b'aiesz32 to thoroughly admixit with fuel injected into the'burner through afuel nozzle 33 in the housing. The combustible mixture so formed is ignited by suitable means, such as the illustrated spark plug 34, and cxhausted or ejected into the. combustion chamber 25 throughthe open end oflthe burner, wherein combustion continues until complete, the exhaust gases then being ledthrough the'conduits 16 and the hollow walls 15 of the upper tubes 11 to the` exhaust stack 19, from whence theyare exhausted.A For. regulating the volume of air admitted into the. air chamber 26, the inner end of the` lower` tube 10is closed bya xed end plate 35 having one ormoreopenings 36,011 the outer face of which ispiv-'V ota'lly mounted anadjustable shutter 37, having corresponding openings 38, by which the extent of the exposure'of the openings 36 in the end plate can be Varied asvdesiredz.y To` minimize disturbance of the airflowing therepast, the` closed `end 28 of the burner may, as shown, .be curved orv rounded;

Forced draft both'of ltheair to be warmed for drying a crop and of thezair'a'dmitted to the air chamberfor combustion-,is' obtained bya single fan or blower 39 `mounted concentrically of the casing 8, intermediate the inner end offthe `heatexchangerand the inlet or intake end 40,01?` thefcasing, and 'supported'in the casing by an annular ring or collar 41. TheA fan is contained or included longi-` tudinally-or axially of the casing within an inturned ani. nular ange or. baffle 42, which is attached or connected to the outer or discharge end 43 of the collar. Since a-relatively-large volume of warmed air is required for the bin,y elevator" or other large space in'which crops are dried,` the fan 39'is multibladed and of a diameter sub-` inside diameter of the casing' may` be connected adjacent the outer end of its shaft a multisheaved pulley 47 drivably connectedrthrough V- belting 48 tora drivepulley 49` of an electric or other motor-50'.l The `motor 50 may conveniently `be housed or' enclosed "in a-housing 51 mounted on top of thecasing 8; and` accessible through in` Figure4; the `fan-motor is utilized to drive a' fuel pump 53;?mountedexteriorly ofthe casing, through a take-off:y pulley/54.- on `the fanxshaft, `for supplying 'fuelfroma suit= ablevstoragewtank (notshown) to the"nozzle.33.` of. the burner through a fuel line 55. For the illustrated position of the pump 53, the fuel line, intermediate the pump and nozzle, is looped into the housing 51 and is there provided with a hand valve 56 by which the fuel ow can be adjusted in accordance with the reading of a pressure gauge 57. Also in the fuel line within the housing is a solenoid-actuated valve 58 operated by a a sliding panel 52. As shownV trically connected to the spark plug or other tiring deviceV 35 through a transformer or the like 60. A separate starting switch 61 is preferably provided within the housing 51 for the motor 50, this andother controls being accessible through the aforementioned sliding panel 52.

To prevent debris from being swept or sucked into the casing by the entering air, the intake end 40 of the casing is covered by a screen 62. The drier of the` present invention is also provided with means both for limiting or controlling the temperature of the outlet air and for shutting off 4the drier in case of llame failure. Both of the illustrated means are thermostatic controls, that 63 for limiting the air temperature being mounted on the casing adjacent its outlet end 12, and having a temperature sensitive element ,64 projecting into the air stream. The other control 65 for llame failure is mounted on the stack 19. Of the two controls, the air temperature control is adapted, through suitable mechanism (not shown) which may be housed within the cover 66 of the motor-starting switch 61, to regulate the inflow of both air and fuel.. The llame failure control 65 operates to shut off the drier until the cause of failure can be determined and correctedz The wiring of both controls may be led to the housing 51 through suitable conduits 67.

For illustrative purposes, the several tubes of .the heat exchanger 9, around or through which the air to be warmed is driven by the fan 39, have been shown as smooth-walled. While the heat transfer so obtainable will be adequate under normal circumstances, due to the circuitous path which the exhaust gases are forced to follow before being vented, the eticiency of the heat exchanger will usually be further enhanced by nning or corrugating its lateral walls to increase the area of its heat transfer surfaces.

Warmed to the desired temperature during its passage through the heat exchanger 9, the outlet air from the drier may be funneled or directed into the bin or other space, whose contents are to be dried, by suitable tubing (not shown) which, for the illustrated mobile drier, will normally be made of canvas or other flexible material to accommodate the drier to different applications.

From the above detailed description, it will be apparent that there has been provided an improved warm air heater which is particularly adapted to dry crops and is both relatively simple in construction and eicient in operation. It should be understood that the described and disclosed embodiment is merely exemplary of the invention and that all modifications are intended to be included which do not depart either from the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. A crop drier comprising a casing, a single-walled primary heat exchanger mounted in said casing, said primary exchanger being dividedrinto an air chamber adjacent an inlet end thereof and a combustion chamber, a pair of hollow-walled secondary heat exchangers supported in superposed relation on and having the hollow interiors of their walls connected to said combustion chamber of said primary exchanger, said exchangers being arranged side-by-side longitudinally of said casing, a jet burner in and having radial entrance ports within said air chamber, said burner having an axial exhaust port within said combustion chamber, and said burner being disposed longitudinally of and spaced inwardly of and within the longitudinal and lateral contines of said primary ex-l changer, said ai'r chamber having an axial opening for admitting combustion air therethrough to said inlet ports of said burner, and a fan associated with said casing for forcing air through said exchanger and said opening.

2. A crop drier comprisinga casing, a single-walled primary heat exchanger mounted in said casing, said primary exchanger being divided into an air chamber adjacent an inlet end thereof and a combustion chamber, a pair of hollow-walled secondary heat exchangers supported in superposed relation on and having the hollow interiors of their walls connected to a combustion chamber in said primary exchanger, said exchangers being arranged sideby-side axially of said casing, a jet burner in and having radial entrance portswithin said air chamber, said burner having an axial `exhaust port within said combustion chamber, and said burner being disposed longitudinally of and spaced inwardly of and within the lateral and longitudinal confines of said primary exchanger, said air chamber having an axial opening for admitting combustion air therethrough to said inlet ports of said burner, a fan associated with said casing for forcing air through said exchanger and said opening, and a control associated with said casing for controlling the temperature of outlet air from said casing.

3. A crop drier comprising a cylindrical casing, a heat exchanger within said casing and including a tube disposed longitudinally and of lesser outside diameter than the inside diameter of said casing, means dividing said tube axially into an air chamber adjacent its inlet end and a combustion chamber, a jet burner in said air chamber and including a housing and a fuel nozzle therein, said housing having entrance ports in said air chamber and an exhaust port open to said combustion chamber and being the yconnection through said dividing means between said chambers, said air chamber having an axial opening for admitting air therethrough into said jet burner, means associated with said opening for regulating the supply o f air to said burner, and a fan mounted in said casing for forcing air over said heat exchanger and through said opening in said air chamber.

4. A crop drier comprising a cylindrical casing, a heat exchanger within said casing and formed of a plurality of connected tubes disposed sde-by-side longitudinally of said casing, means dividing one of said tubes axially into an vair chamber adjacent its inlet end and a combustion chamber, a jet burner in said air chamber and including a housing and a fuel nozzle therein, said housing having entrance ports in said air chamber and an exhaust port open to said combustion chamber and being the connection through said dividing means between said charnbers, said air chamber having an axial opening for admitting air therethrough into said jet burner, means associated with said opening for regulating the supply of air to said burner, and a fan mounted concentrically of said casing for forcing air over said heat exchanger and through said opening in said air chamber.

5. A crop drier comprising a cylindrical casing, a heat exchanger within said casing and formed of connected tubes disposed side-by-side longitudinally of said casing, means dividing one of said tubes axially into an air chamber adjacent its inlet end and a combustion chamber, a jet burner in said air chamber and including a housing and a fuel nozzle therein, said housing having entrance ports in said .air chamber and an exhaust port open to said combustion chamber and being the connection through said dividing means between said chambers, said air chamber having an axial openingr for admitting air therethrough into said jet burner, a shutter for varying said opening and regulating the supply of air to said burner, a fan mounted concentrically of said casing for forcing air over said heat exchanger and through said opening in said air chamber, a baffle associated with said fan for deflecting said air inwardly toward said heat exchanger, and a control associated with said burner and fan for controlling therethrough the temperature of the outlet air from saidcasing.

References Cited in the le of this patent UNITED STATES PATENTS 2,510,645 yMcMahan June 6, 1950 

